Method and apparatus for treating a tow of filaments or threads in a limited space



Oct. 1], 1955 KEGGlN 2,720,443

METHOD AND APPARATUS FOR TREATING A TOW OF FILAMENTS OR THREADS IN A LIMITED SPACE Filed Feb. 12, 1951 INVENTOR JAMES FAFQGHER KEGGIN ATTORNEYS United States Patent My METHOD AND APPARATUS FOR TREATING A TOW OF FILAMENTS OR THREADS IN A LIM- ITED SPACE James F. Keggin, Seamill, Scotland,assignor to Imperial Chemical Industries Limited, a corporation of Great Britain Application February 12, 1951, Serial No. 210,47 0 Claims priority, application Great Britain March 21, 1950 11 Claims. (Cl. 8-1511) The present invention relates to a method of treating a tow of filaments or threads in a limited space and is particularly concerned with a method of treating in nontensioned condition a continuous tow of artificial filamentary products with a treating liquid having a specific gravity less than the specific gravity of the tow.

It has been found difi'icult e. g. to treat in asatisfactory manner a continuous travelling tow of artificial filamentary products of vegetable seed globulins or phospho-proteins by allowing these products to fall into and accumulate or form folds in concentrated salt solutions and of the kind which are of lower specific gravity than the said tow and are contained in a static tank of large but reasonable dimensions. The tow is found to form a compact mass difficult for the liquid to penetrate and to become entangled if a sufficient length is left to accumulate in a tank for it to receive the necessary time of treatment in the treating liquid.

Unsatisfactory results are also obtained if a tow of such filaments or threads is permitted to drop into and to form folds in the aforesaid liquids flowing through a static trough as tangling again occurs and the degree of contact between the liquid and the individualfilaments of the tow is poor leading to incomplete treatment.

The object of the present invention is to provide a method of treating. in a non-tensioned condition a continuous tow of filamentary products with a treating liquid having a specific gravity less than the specific gravity of the tow which will ensure intimate contact between the individual filaments of a tow and the treating liquid.

According to the present invention the method of treating in a non-tensioned condition a continuous tow of filamentary products with a treating liquid having a specific gravity less than the specific gravity of the tow comprises introducing a current of the treating liquid and the tow into the inlet end of a tubular structure portion having its lower surface inclined downwards in the direction of flow of said liquid and arranging that the speed of the treating liquid and the inclination downwards of said lower surface are such. that the desired quantity of tow collects on said lower surface and that the portion of the tow withdrawn from out of the treating liquid at the exit end of the tubular structure has remained inthe treating liquid for the desired period of time. i

The tubular structure portion having its lower surface inclined downwards can preferably be one arm of a U tube, the other arm of the U tube serving as the exit end for the tow and the current of treating liquid. On theother hand the tubular structure portion having its lower surface inclined downwards can be positioned in a trough so that the treating liquid will collect and fill the. trough to the height desired as it leaves the lower end of the tubular structure portion.

Preferably the tow is introduced into the said tubular structure portion by means of a current of said treating liquid passing through another tubular structure 2,720,443 Patented Oct. 11, 1955 portion of narrower width and leading to said tubular structure portion. If desired the said tubular structure portion of narrower width ends in a portion of progressively increasing width as it enters the aforesaid tubular structure portion havings its lower surface inclined downwards. In accordance with this embodiment of the invention the treating liquid and the tow pass through the narrower bore of the tubular structure of narrower diameter at relatively high speed. The speed of the liquid here, which is controlled by the head or difference in level of the liquid at the entrance to the narrower tube and the overflow of the liquid after having left the exit of the tubular structure portion having its lower surface inclined downwards or alternatively the pumping pressure, must be at least as great as that of the tow at this point. On entering the tubular structure portion having its lower surface inclined downwards the tow folds irregularly as the velocity of the liquid drops and forms a loose column of fibre which moves slowly down the tube on the lower surface. The speed of travel in this tubular structure portion is controlled to some extent by the speed of liquid flow in the tube which depends on the relative bores of this tube and the narrower tube and the initial speed of the tow and also on the inclination downwards of the wider tube, for the fibre being more dense than the liquid tends to slide down the tube. It is the time of treatment of the fibre, which is the time taken to traverse the narrower and wider tubes which depends on the above factors controlling the speed of travel and also on the length of the wider tube, or more accurately on the length of the column or folded fibre allowed to accumulate in the wider tube before being withdrawn. For a tow of given size and rate of delivery the speed of liquid in the narrower tube, i. e. the head is adjusted to be somewhat greater than the tow speed. The bore size of the narrower tube is a matter of convenience. The size of the wider tube is determined by the required time of treatment. It is possible to vary this time within very wide limits in the same apparatus as the fibre may be drawn through both tubes with very little accumulation in a fraction of a minute, or may be allowed to accumulate in a long column the length of which is determined by the length of the wider tube, so that the time of passage may take many minutes.

Preferably the lower surface of the first mentioned tubular structure portion is inclined at an angle lying between 5 and 45 to the horizontal.

The tubular structure portion having the narrower bore preferably ends with a portion of progressively increasing width, approaching or equal to the width of the first mentioned tubular structure portion having the wider width, in order to prevent excessive turbulence of the liquid flow and a possible entangling of the filaments forming the tow as it sinks in the treating liquid on entering the first mentioned tubular structure portion having the wider width.

Apparatus for treating in accordance with the preferred method of the invention in a non-tensioned condition a continuous tow of filamentary products with a treating liquid having a specific gravity less than the specific gravity of the tow comprises in combination a constant level feed cone, a tubular structure portion leading to a tubular structure portion substantially wider than the narrowest part of the aforementioned tubular structure, wherein the lower surface of the wider tubular structure is of desired length and of desired inclination and particularly advantageous for treating continuous travelling tows of artifical filamentary products of protein with concentrated saline solutions of the kind which are of lower specific gravity than said tows.

The invention is illustrated by the following example in which the parts are parts by weight except where otherwise stated and with reference to the drawing accompanying the specification.

The drawing is a diagrammatic front elevation of apparatus suitable for carrying out the method of the invention.

Example A matured caustic soda solution of groundnut globulin prepared from a solution containing 20 parts peanut globulin, 1.25 parts sodium hydroxide, 1.0 part of sodium sulphite and 77.75 parts water is extruded into the coagulating bath containing 200 gm./l. sodium sulphate and 20 gm./l. sulphuric acid. The resulting tow 1 of 15,000 filaments each of 3 to 4 denier is taken up on godet 2 having a peripheral speed of 30 metres per minute and passes to godet 3 having the same peripheral speed.

The tow 1 then travels vertically downwards into the constant level feed cone 4 where it is picked up by a relaxing solution which enters the feed cone through a pipe 5 and is then carried through the tube 6 and the glass cone 7 into the inclined tube 8 which is one arm of a U tube, the other arm being 9. The tube 6 is of 4 inch diameter and the glass cone 7 is 4 inches in diameter at the open end. The composition of the relaxing solution is 250 gms. of sodium sulphate per litre of solution and it enters and leaves the tube 8 at 20 C. The speed of the liquid flow through tube 6 is controlled by the difference in levels of the liquid at the inlet cone 4 and the overflow at the exit end of the tube 9 which in this case is 4 inches. The U tube 8, 9 is of glass 6 inches in diameter and the inclined tube 8 is 6 feet long and is inclined sothat the lowest portion of this tube is 14 inches below the inlet end. The speed of the tow at the feed cone 4 is 30 meters per minute. On entering the inclined tube 8 through the funnel 7 the tow forms a loose column about 4 feet long against the lower surface of the tube 8 filling roughly about A of the cross-sectional area and is then removed at the exit end of the tube 9 by a godet 10. The peripheral speed of this godet is adjusted to 19 metres per minute so that the passage through the tube 8 is constant and about 3 minutes which is sufficient to relax the protein filaments. The filaments thus relaxed are then treated in known manner so as to elfect their insolubilisation, that is to say, so as to make these filaments resistant to treatment for 90 minutes at 97 in a testing bath containing 0.1% sulphuric acid and 0.25% sodium sulphate.

What I claim is:

1. A method of treating in a non-tensioned condition without tangling a continuous tow of artificial protein filaments which comprises introducing a tow of said filaments into the upper end of a longitudinally confined downwardly inclined treating zone of relatively small crosssectional area, propelling said tow with a current of treating and carrying liquid having a specific gravity less than the specific gravity of said tow through said first treating zone downwardly from the upper end thereof, said liquid completely filling said zone, moving said liquid together with the tow therein out of said first treating zone and directly therefrom into the upper end of a second longitudinally confined downwardly inclined treating zone of relatively large cross-sectional area in comparison with said first zone, said liquid completely filling said second zone, carrying said tow through said second zone by moving said liquid in a non-turbulent condition through said second treating zone and Withdrawing said tow from the lower end of said second treating zone.

2. A method as recited in claim 1 in which said liquid is moved out of said second treating zone into a third 1ongitudinally confined upwardly inclined treating zone and said tow is withdrawn from the lower end of said second treating zone through said third zone.

3. A method as recited in claim 1 in which said first treating zone is of progressively increased cross-sectional area at its point of junction with said second treating zone.

4. A method as recited in claim 1 in which the lower portion of said first treating zone and said second zone are inclined at an angle lying between 5 and 45 to the horizontal.

5. A method as recited in claim 1 in which said treating liquid comprises a concentrated saline solution.

6. Apparatus for treating in a non-tensioned condition without tangling a continuous tow of artificial protein filaments with a treating liquid having a specific gravity less than the specific gravity of said tow comprising a first downwardly directed elongated narrow tubular member, means for continuously supplying treating liquid'and said tow to an upper portion of said first tubular member, a second downwardly inclined elongated tubular member of substantially greater cross-sectional area than the narrowest part of said first tubular member, the lower end of said first tubular member communicating. with the upper end of said second tubular member, means to axially confine the lower end of said second tubular member and means to maintain a constant head of liquid whereby the treating liquid delivered to the upper portion of said first tubular member flows down said first tubular member into and through said second tubular member at decreased velocity to permit the tow which emerges from the lower end of said first tubular member into said second tubular member where the treating liquid flows at reduced velocity to fold irregularly and form a loose elongated column of fiber in the treating liquid which moves slowly down the lower inner confining surface of said second tubular member.

7. Apparatus as recited in claim 6 in which said means to axially confine the-lower end of said second tubular member is a third upwardly inclined tubular member, the lower end of which communicates with the lower end of said second tubular member, said head of liquid being maintained by providing said third tubular member with an outlet for liquid positioned below the portion of said first tubular member where said treating liquid is supplied.

' 8. Apparatus as recited in claim 7 in which said means for supplying treating liquid to an upper portion of said first tubular member includes means for maintaining a constant liquid level in said first tubular member.

9. Apparatus as recited in claim 7 in which the first tubular member is provided with an end portion of progressively increasing cross-sectional area for communication with said second tubular member whereby turbulent flow is prevented.

10. Apparatus for treating in a non-tensioned condition without tangling a continuous tow of artificial protein filament which'comprises a substantially U-shaped tubular treating chamber, said chamber having a mouth portion at the upper end of one leg thereof, means for delivering a filament tow to said mouth portion for passage from said mouth portion through said U-shaped chamber, means for delivering a treating liquid to said mouth portion, the leg of said U-shaped chamber having said mouth portion at the upper end thereof being of relatively small cross-sectional area from the point of entrance of said tow to the lower base portion of said chamber at which point the base portion of said chamber becomes of increased cross-sectional area, said base portion being inclined downwardly away from said first named leg, means for withdrawing said tow from the other legof said U-shaped chamber, said other leg having liquid discharge means positioned below the level of said mouth portion.

- 11. An apparatus as recited in claim 10 in which said liquid discharge means is positioned above the upper surface of the lower end of said lower base portion of said chamber.

References Cited in the file of this patent 5 UNITED STATES PATENTS 1,029,866 Haskell June 18, 1912 1,153,004 Althouse Sept. 7, 1915 1,702,535 Cole Feb. 19, 1929 1,778,380 Conrad Oct. 14, 1930 10 1,825,478 Rowley Sept. 29, 1931 6 Nai Sept. 27, 1938 Von Recklinghausen et a1. "Mar. 7, 1939 Dursteler June 11, 1940 Ufnowski Mar. 2, 1943 Lyem June 5, 1945 Rormell Aug. 21, 1945 Thomson et a1. May 29, 1951 FOREIGN PATENTS Germany Aug. 13, 1930 

10. APPARATUS FOR TREATING IN A NON-TENSIONED CONDITION WITHOUT TANGLING A CONTINUOUS TOW OF ARTIFICIAL PROTEIN FILAMENT WHICH COMPRISES A SUBSTANTIALLY U-SHAPED TUBULAR TREATING CHAMBER, SAID CHAMBER HAVING A MOUTH PORTION AT THE UPPER END OF ONE LEG THEREOF, MEANS FOR DELIVERING A FILAMENT TOW TO SAID MOUTH PORTION FOR PASSAGE FROM SAID MOUTH PORTION THROUGH SAID U-SHAPED CHAMBER, MEANS FOR DELIVERING A TREATING LIQUID TO SAID MOUTH PORTION, THE LEG OF SAID U-SHAPED CHAMBER HAVING SAID MOUTH PORTION AT THE UPPER END THEREOF BEING OF RELATIVELY SMALL CROSS-SECTIONAL AREA FROM THE POINT OF ENTRANCE OF SAID TOW TO THE LOWER BASE PORTION OF SAID CHAMBER AT WHICH POINT THE BASE PORTION OF SAID CHAMBER BECOMES OF INCREASED CROSS-SECTIONAL AREA, SAID BASE PORTION BEING INCLINED DOWNWARDLY AWAY FROM SAID FIRST NAMED LEG, MEANS FOR WITHDRAWING SAID TOW FORM THE OTHER LEG OF SAID U-SHAPED CHAMBER, SAID OTHER LEG HAVING LIQUID DISCHARGE MEANS POSITIONED BELOW THE LEVEL OF SAID MOUTH PORTION. 